if one were to count the Los Angeles metropolitan area as a separate nation, it would have the world's eleventh largest gross national product, that is

if the Los Angeles metropolitan area is counted as a separate nation, it has the world's eleventh largest gross national product, that being

if the Los Angeles metropolitan area were a separate nation, it would have the world's eleventh largest gross national product,

were the Los Angeles metropolitan area a separate nation, it will have the world's eleventh largest gross national product, which is

when the Los Angeles metropolitan area is counted as a separate nation, it has the world's eleventh largest gross national product, thus